CVE-2015-8109 in System Update
Summary
by MITRE
Lenovo System Update (formerly ThinkVantage System Update) before 5.07.0019 allows local users to gain privileges by making a prediction of tvsu_tmp_xxxxxXXXXX account credentials that requires knowledge of the time that this account was created, aka a "temporary administrator account vulnerability."
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Analysis
by VulDB Data Team • 12/21/2020
The vulnerability identified as CVE-2015-8109 represents a critical privilege escalation flaw in Lenovo System Update software, formerly known as ThinkVantage System Update. This issue affects versions prior to 5.07.0019 and stems from a predictable temporary administrator account mechanism that exposes the system to local privilege escalation attacks. The vulnerability specifically targets the tvsu_tmp_xxxxxXXXXX account naming convention and its associated credential generation process, which follows a deterministic pattern based on temporal factors.
The technical implementation of this flaw involves the predictable creation of temporary administrator accounts within the Lenovo System Update framework. Attackers can exploit this by calculating the specific account credentials through temporal prediction, requiring knowledge of when the temporary account was created. This approach aligns with CWE-254 weakness category, specifically addressing security mechanisms that are predictable or deterministic, making them vulnerable to exploitation by adversaries who can anticipate the system's behavior. The vulnerability operates under the principle of temporal prediction where the system generates account names and passwords following a known algorithm based on timestamp information, creating a window of opportunity for exploitation.
From an operational impact perspective, this vulnerability enables local attackers to escalate their privileges from standard user level to administrative access without requiring additional authentication credentials or complex attack vectors. The exploitability of this flaw is enhanced by the fact that it requires minimal information gathering beyond basic system time knowledge, making it particularly dangerous in environments where local access is possible. The vulnerability essentially creates a backdoor mechanism that allows attackers to bypass normal authentication procedures and gain full administrative control over the affected system. This type of attack pattern is consistent with techniques described in the MITRE ATT&CK framework under privilege escalation tactics, specifically targeting credential access and defense evasion categories.
The mitigation strategies for this vulnerability should focus on immediate software updates to version 5.07.0019 or later, which addresses the predictable credential generation issue. Organizations should also implement monitoring for suspicious account creation patterns and ensure that temporary administrator accounts are properly secured and monitored. Additional security measures include restricting local access to systems where this software is installed, implementing account lockout mechanisms, and conducting regular security assessments to identify similar predictable patterns in other system components. The vulnerability demonstrates the importance of secure credential generation practices and highlights the need for robust entropy in temporary account creation processes. Security professionals should also consider this issue in the context of broader system hardening practices and ensure that similar temporal prediction vulnerabilities are identified and addressed across all system components to prevent analogous attacks.